In each decade after 1700, I count all mentions in books of "Planet " for each planet and all variations of capitalization. At each decade I then rank the planets from most to least mentions. I searched for the combination of Planet+Name to avoid possible contamination (e.g., from the element Mercury, or the goddess Venus).

For those planets not known in antiquity, I mark their place with a dotted line until discovery, which is marked with a circle.

Since Neptune was discovered mid-decade, its popularity appears to take off before discovery due to the way I smoothed the data.

Some very interesting trends are apparent. My favorite is the meteoric rise of the popularity of the phrase 'Planet Earth' in the early 20th century, and now Earth occupies the top spot. I think this is evidence of Earth being, for the first time, placed in a cosmic context in the public consciousness — the public realization that Earth is a planet, not the planet.

Its worth noting that this data goes up to 2008, so Saturn is at a bit of a disadvantage. The Cassini mission has done wonders to share the beauty of the Saturn system with the public since its arrival in 2004, so I imagine a version of this plot made in a few years' time will show a spike in Saturn's popularity.

Also: poor Pluto gets no love! This must be remedied! Maybe a visit from New Horizons will help.